"You were both very aggressive with your behaviour, using bad language and roof tiles were thrown as missiles.”

Deborah Davies, defending, said: “Mr Oliver had lived with Mr Lewis and his partner for a couple of months but was the cause of tension.”

Oliver was sentenced to a total of 16 weeks behind bars for previous assaults: on February 27, he spat in the face of estate agent Stephen Tudor at an address in Pwllheli, where Oliver lived with his mother.

Damage to the roof of the Prichard Jones Institute, Newborough following the incident (Image: Arwyn Roberts)

Mr Tudor had come to inspect the property having served an eviction notice for unpaid rent.

On June 6 last year Oliver was seen on CCTV punching Katie Cross in the face in Caernarfon.

He was given a community order which he breached.

Lewis and Oliver will be sentenced for charges related to the siege on June 11.